Extraction of important target analyte(s) form a sample matrix for concentrating, purifying or otherwise isolating the target analyte can be challenging. The type of target analyte, the amount or concentration of the target analyte in the sample matrix, the sample matrix components, and the desired purity or concentration of the extracted analyte are all variables that can affect the extraction of a target analyte. The extraction of nucleic acids, for example, from biological samples for the purpose of diagnostic procedures is an increasingly important capability for medical science. The science of whole-genome sequencing is emerging as a powerful diagnostic technology that is becoming accessible in first world countries for routine medical services.
While the technology for sequencing DNA has advanced tremendously, obtaining DNA from a biological sample remains a challenge. Common processes to obtain DNA still involve invasive, labor intensive and time consuming techniques using specialized equipment. For example, genomic DNA extraction necessarily begins with the lysis of cells that contain the DNA to be analyzed. After lysis, only two commonly used DNA isolation procedures exist. One is phenol-chloroform extraction followed by DNA precipitation. This process is time consuming, requires multiple manipulations of the sample, requires refrigeration, centrifugation and evaporation, and finally, generates toxic waste. The other involves DNA adsorption on a silica matrix. This process is also labor intensive, time consuming, requires the use of chaotropic salts that must be disposed of as hazardous waste, and finally, also requires specialized equipment. DNA extraction methods that are simpler, generate less waste and require less equipment will further increase the availability of genetic analysis methods.
Currently, blood samples are the most reliable source for nucleic acids to be used in whole-genome sequencing or other forms of genetic testing such as Sanger Sequencing, SNP Arrays, RFLP analysis, and forensic methods. Other DNA sources, such as saliva and buccal swabs, are less invasive to collect than blood but are much more variable in matrix composition and DNA content. All of these samples tend to yield dilute DNA or DNA extracts contaminated with inhibitors that interfere with downstream processing, e.g., enzymological reactions. Nevertheless, the ease of collection makes these samples an attractive DNA source.
As sequencing technology advances, the amount of DNA required for successful sequencing continues to decrease. The demand for simple at-home sample collection also continues to increase. The ability to extract adequate amounts of DNA from typical buccal or saliva samples as well as a method of increasing the concentration of DNA in low-yield buccal samples can increase the success rate of DNA sequence analyses.
Self-wicking materials can include a number of different materials, including monoliths, absorbent pads, etc. Macroporous monolithic materials are used in the field of separations science, most commonly as chromatographic media. The two most common base materials for monoliths are silica gel and acrylic polymers. Both can be made with the mechanical strength necessary to withstand the extreme pressure of HPLC or the mechanical stresses of industrial-scale purification processes. Polymeric monoliths are also frequently used in solid-phase extraction consumables and in microfluidic devices. For example, polymeric monoliths are popular components in microfluidic chips because they can be cured-in-place with masked UV irradiation to generate integrated microscale chromatography columns.
U.S. Patent Publication No. 2014/0127669 describes the use of polymeric monoliths in the field of sample preservation as an alternative to paper-based dry blood-spot (DBS) DNA preservation matrices. Blood spots spiked with small molecule pharmaceuticals dried on a monolith film were treated to recover the pharmaceuticals.
The concentrator and related methods of the present disclosure, using self-wicking monoliths, can provide a simple, stand-alone target analyte isolation and concentration system that minimizes the need for hazardous chemicals and specialized equipment. For example, the concentrator of the present disclosure can provide the ability to extract adequate amounts of biological targets, e.g., nucleic acid, from typical clinical samples and increase the concentration of nucleic acid in these samples to increase the efficiency of various testing methods, e.g., DNA sequencing. The concentrator of the present disclosure can also reduce the chemicals and equipment needed to obtain a concentrated target analyte, e.g., DNA sample.